The present invention relates to signal generators and more particularly the invention relates to VHF frequency signal generators of the type which permit selection of the generation of frequencies over a wide range.
Signal generators of the type to which the invention pertains are used for example as reference signal generators. In order to ensure a rather wide range of application for a single product, the signal generator should permit selection of frequencies to be generated within a wide range, but each selected frequency to be selected should be adjustable to remain within very small tolerances which should be the same for any frequency within the range of interest. Providing for adjustment of any frequency with a range from e.g. 1 MHz to about 500 MHz or higher in steps of, for example, 1 KHz poses a significant problem particularly when each of these signals should remain stable to, say one-thousandth of 1 percent.